#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <math.h>
int main()
{
	double m, n;
	while (scanf("%lf %lf", &n, &m) != EOF)
	{
		double sum = 0;
		for(int i = 0; i<m; i++)
		{
			sum += n;
			n = sqrt(n);
		}
		printf("%.2lf\n", sum);
	} 
	return 0;
}













